/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.sinosoft.monitor.org.objectweb.asm.tree.analysis;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import com.sinosoft.monitor.org.objectweb.asm.Opcodes;
import com.sinosoft.monitor.org.objectweb.asm.Type;
import com.sinosoft.monitor.org.objectweb.asm.tree.AbstractInsnNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.FieldInsnNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.InvokeDynamicInsnNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.LdcInsnNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.MethodInsnNode;

/**
 * An {@link com.sinosoft.monitor.org.objectweb.asm.tree.analysis.Interpreter} for {@link com.sinosoft.monitor.org.objectweb.asm.tree.analysis.SourceValue} values.
 *
 * @author Eric Bruneton
 */
public class SourceInterpreter extends Interpreter<SourceValue> implements
		Opcodes {

	public SourceInterpreter() {
		super(ASM4);
	}

	protected SourceInterpreter(final int api) {
		super(api);
	}

	@Override
	public SourceValue newValue(final Type type) {
		if (type == Type.VOID_TYPE) {
			return null;
		}
		return new SourceValue(type == null ? 1 : type.getSize());
	}

	@Override
	public SourceValue newOperation(final AbstractInsnNode insn) {
		int size;
		switch (insn.getOpcode()) {
			case LCONST_0:
			case LCONST_1:
			case DCONST_0:
			case DCONST_1:
				size = 2;
				break;
			case LDC:
				Object cst = ((LdcInsnNode) insn).cst;
				size = cst instanceof Long || cst instanceof Double ? 2 : 1;
				break;
			case GETSTATIC:
				size = Type.getType(((FieldInsnNode) insn).desc).getSize();
				break;
			default:
				size = 1;
		}
		return new SourceValue(size, insn);
	}

	@Override
	public SourceValue copyOperation(final AbstractInsnNode insn,
	                                 final SourceValue value) {
		return new SourceValue(value.getSize(), insn);
	}

	@Override
	public SourceValue unaryOperation(final AbstractInsnNode insn,
	                                  final SourceValue value) {
		int size;
		switch (insn.getOpcode()) {
			case LNEG:
			case DNEG:
			case I2L:
			case I2D:
			case L2D:
			case F2L:
			case F2D:
			case D2L:
				size = 2;
				break;
			case GETFIELD:
				size = Type.getType(((FieldInsnNode) insn).desc).getSize();
				break;
			default:
				size = 1;
		}
		return new SourceValue(size, insn);
	}

	@Override
	public SourceValue binaryOperation(final AbstractInsnNode insn,
	                                   final SourceValue value1, final SourceValue value2) {
		int size;
		switch (insn.getOpcode()) {
			case LALOAD:
			case DALOAD:
			case LADD:
			case DADD:
			case LSUB:
			case DSUB:
			case LMUL:
			case DMUL:
			case LDIV:
			case DDIV:
			case LREM:
			case DREM:
			case LSHL:
			case LSHR:
			case LUSHR:
			case LAND:
			case LOR:
			case LXOR:
				size = 2;
				break;
			default:
				size = 1;
		}
		return new SourceValue(size, insn);
	}

	@Override
	public SourceValue ternaryOperation(final AbstractInsnNode insn,
	                                    final SourceValue value1, final SourceValue value2,
	                                    final SourceValue value3) {
		return new SourceValue(1, insn);
	}

	@Override
	public SourceValue naryOperation(final AbstractInsnNode insn,
	                                 final List<? extends SourceValue> values) {
		int size;
		int opcode = insn.getOpcode();
		if (opcode == MULTIANEWARRAY) {
			size = 1;
		} else {
			String desc = (opcode == INVOKEDYNAMIC) ? ((InvokeDynamicInsnNode) insn).desc
					: ((MethodInsnNode) insn).desc;
			size = Type.getReturnType(desc).getSize();
		}
		return new SourceValue(size, insn);
	}

	@Override
	public void returnOperation(final AbstractInsnNode insn,
	                            final SourceValue value, final SourceValue expected) {
	}

	@Override
	public SourceValue merge(final SourceValue d, final SourceValue w) {
		if (d.insns instanceof SmallSet && w.insns instanceof SmallSet) {
			Set<AbstractInsnNode> s = ((SmallSet<AbstractInsnNode>) d.insns)
					.union((SmallSet<AbstractInsnNode>) w.insns);
			if (s == d.insns && d.size == w.size) {
				return d;
			} else {
				return new SourceValue(Math.min(d.size, w.size), s);
			}
		}
		if (d.size != w.size || !d.insns.containsAll(w.insns)) {
			HashSet<AbstractInsnNode> s = new HashSet<AbstractInsnNode>();
			s.addAll(d.insns);
			s.addAll(w.insns);
			return new SourceValue(Math.min(d.size, w.size), s);
		}
		return d;
	}
}
